ES2730967T3 - Extraction catheter and excision apparatus - Google Patents

Abstract

A catheter (1) for the removal of tissue comprising: - a telescopic tubular body (4) which in turn comprises an outer tubular body (4a) and an inner tubular body (4b) concentric with each other, and a guiding element rod type (5) housed at least partially in the inner tubular body (4b) with at least one free end (5a) projecting from the inner tubular body (4b) in correspondence with a distal end of the telescopic body (4); - a positioning head (2, 2 ", 2" ', 2º, 2 *, 2 ^) and a removal head (3) in correspondence with the distal end of the telescopic body (4), the positioning head being ( 2, 2 ", 2 '", 2º, 2 *, 2 ^) located near the free end (5a) of the rod-type guide, and the removal head (3) being in the vicinity of the positioning head (2, 2 ", 2" ', 2º, 2 *, 2 ^), in a remote position with respect to the free end (5a); - a control handpiece at a proximal end of the telescopic body (4) coupled with the guide element (5), the extirpation head (3), the positioning head (2, 2 ", 2" ', 2º , 2 *, 2 ^) and the telescopic tubular body (4); wherein the removal head (3) comprises at least two removal elements or lobes (3a) that can be moved between a rest position in which they are housed in the outer tubular body (4a) and an operating position in that protruding from the outer tubular body (4a) as a lobe; each of the excision elements or lobes (3a) comprising: - a continuous excision electrode (3b) that extends without interruption over a peripheral peripheral portion of each lobe (3a), substantially along an arc of circumference that it has a longitudinal axis of the rod-like guiding element (5) as its center; - two lateral portions (3c) of the lobe (3a) connected, each, with one end of the removal electrode (3b), in correspondence with a curved section, each removal lobe (3a) being individual and different from another lobe excision (3a) of the excision head, all excision lobes (3a) of the excision head being connected separately to an individual electric power generator to cause a radiofrequency excision in an excision electrode in the activated state (3b) , characterized in that the lateral portions (3c) and the removal electrode (3b) are integral with each other, formed by means of the same folded metal conductor, and in which each removal lobe (3a) is produced with a single Nitinol having a circular section with a diameter D, and, since L is the linear length of the excision electrode, there is the following D / L ratio, which varies between 0.015 and 0.025.

Description

DESCRIPTION

Extraction catheter and excision apparatus

Technical field

The present invention relates to the general field of catheters and excision apparatus for the removal of human tissue or, more generally, for animals.

State of the art

Various types of removal catheters are known in the state of the art.

In general, the term "excision" refers, in the medical field, to the treatment of a suitable tissue for the removal of a superficial part of the same tissue or its necrotization and / or to cause healing thereof. The removal referred to in this invention is specifically intended to interrupt the electrical continuity of the tissue in correspondence with the area treated by removal.

In this sense, the removal can take place with a series of treatments, for example, by means of an electric current, with heat, with cryogenics, radiofrequencies or other forms of treatment.

A first example of a radiofrequency excision catheter is one capable of performing localized excisions: in fact, it has a real excision tip corresponding to its free end.

In treatment, the catheter is inserted through percutaneous access and is taken to the area to be removed.

Then, the surgeon activates the tip of excision and performs the excision of the tissues by means of a continuous movement of approximation / distancing of the tip of excision of the tissue, necessary not to maintain an excessively long contact of the tip with the tissue, with consequent damage that can be critical.

Therefore, the excised area is defined by the combination of the excised punctate areas.

This operation is particularly delicate, since excessively prolonged contact of the tip with the tissue can lead to serious injury to the latter.

Consider, for example, the removal of the antrum from the pulmonary veins in the case of atrial fibrillation: the antrum of the veins to be removed is located in correspondence with a set of veins of the heart; Excessively prolonged contact of the removal tip with the tissue could lead to perforation of the heart wall, and if not treated immediately, it could have fatal consequences for the patient.

On the other hand, the removal maneuver itself must also be long enough to ensure that the removal is effective and does not have to be repeated.

This situation, already complex, becomes even more complex due to the fact that this type of excision generates substantially punctiform excised areas, and consequently, the treatment must be repeated numerous times, in order to join these punctate areas until they form a line of substantially continuous removal to interrupt the electrical continuity of the tissue and isolate the atrium from venous electrical disturbances. Therefore, the intervention has a relatively long duration that requires prolonged sedation of the patient.

Additionally, in order to improve the accuracy of the treatment, the radiofrequency removal catheter described above requires a second separate catheter, that is, a mapping catheter, which obtains information on the position and the effectiveness of the treatment of the individual areas that They are going to be treated.

This implies having to introduce and maneuver two individual catheters, with a relatively high impediment, cost and overall difficulties of the procedure.

Another type of known catheter, especially suitable for the removal of the antrum from the pulmonary veins (for the treatment of atrial fibrillation) is described in international patent application PCT / EP2012 / 056626. This catheter was created to at least partially solve the problems indicated above.

It comprises a positioning head and an excision head and a telescopic tubular body provided with an outer tubular body, an inner tubular body, concentric with each other, and a rod-type guiding element housed at least partially in the inner tubular body, with a free end protruding from the inner tubular body.

The positioning head is located in the vicinity of the free end of the rod-type guiding element, while the removal head is positioned near the positioning head, in a position away from the free end, that is, on the opposite side of the last with respect to the positioning head.

In summary, the positioning head and the removal head can be inflated with the appropriate fluids so that they pass from a resting position in which they are deflated and not expanded, to an operating state in which they are inflated and expanded.

Although this catheter represents a considerable step forward with respect to those that have a "removal tip" described above, it still has several drawbacks.

A first drawback is related to the fact that it has a certain impediment even when it is in a state of rest: in fact, it should be remembered that the catheters are inserted into the patient's veins and taken through them to the treatment areas, which can often be distant from the point of entry (for example, in the treatment of atrial fibrillation, the catheter is inserted into the femoral vein and carried to the heart).

In this regard, it is obvious that it is extremely important to limit the impediment of the catheter in order to facilitate its passage into the veins of the patient undergoing the treatment.

Another drawback is related to the fact that the catheter removal head described therein is an impeller, which, once expanded, has a well defined size: therefore, in an operating state, its size cannot be modified.

This implies knowledge of the exact size of the area to be treated, in order to be able to select the correct catheter, that is, that it has an impeller that, in an expanded state, has a size consistent with that of the area to be It will try.

A further drawback, related again to the size of the impeller described above, is based on the fact that the same catheter cannot be used for different applications, for example, applications in which the size required by the removal head differs significantly (for example, for veins that have a different opening in the same patient).

A further drawback concerns the fact that some excised areas often require a second removal treatment in order to be effective.

An example is the case of the removal of the antrum from a vein: the line of excision in which the tissue is altered by the treatment is substantially a circumference; If an arch of the same is not sufficiently treated, the surgeon must proceed with a new treatment.

The intrinsic characteristics of the catheter described above imply, however, that a new treatment may also involve areas of the circumference that have already been sufficiently treated, thereby exposing the tissue to potential damage.

Another known removal catheter is that described in US2013 / 0103027. In this case, there are two individual heads in the distal portion, an excision head and a positioning head.

The removal head has angled filiform supports in which individual (punctate) removal electrodes are assembled.

A further removal catheter is that described in US2005171536, which shows a catheter according to the preamble of claim 1: also in this case, the removal head has electrodes assembled in a support structure.

The same can be said, in summary, for the catheter described in US 6,893,438.

US 2007/0219546 and US 2006/0084966 show other examples of removal catheters.

Although these types of embodiments are capable of overcoming some of the drawbacks described above with respect to more traditional catheters (with a tip and inflatables), they are, however, relatively complex to build, they require specific conductors for feeding the electrodes and occupy considerable space.

Additionally, it should be noted that during the removal operation with the catheters with individual electrodes, the risk of blood clot formation is relatively high, due to the fact that, as a whole, it is difficult to make the electrodes of each cable of the structure of support adhere perfectly to the surface of the tissue to be removed.

Another problem encountered with the "multi-electrode" catheters described above is due to the individual arrangement of the electrodes: said electrodes, which can be activated with a monopolar or bipolar radiofrequency supply, remove the tissue surrounding the pulmonary veins, leaving, however, gaps between one point of excision and another. In order to fill these gaps, some repeated applications of the same catheter are very often required, or even the introduction of a local catheter and a mapping catheter to identify and complete the removal in areas that have not been fully treated, with a consequent increase in the risk of the procedure for the patient and an increase in the times and costs of the intervention.

In its entirety, radiofrequency excision is more difficult to control due to the parasitic currents that can be generated in the conductors along the catheter, from the (external) generator to the excision head, which can hinder precise control of the amount of power supply.

Objectives of the invention

A first objective of the present invention is to overcome the drawbacks of the known technique.

A second objective of the invention is to provide a catheter for the removal of tissues that is as small as possible and at the same time has an excision profile that is as wide and uniform as possible.

An additional objective is also to allow the removal of only part of the tissue surrounding the removal head, without requiring that other parts already treated correctly be subjected to a new treatment.

A further objective of the invention is to provide a catheter for tissue removal that is capable of shortening the duration of the procedure, thereby reducing the time during which the patient is sedated.

An additional objective is to provide an excision catheter that is safer to use, also in the case of movable tissue walls, and that prevents damage or perforation of the walls.

A further object of the invention is to provide a removal catheter that, when used, has reduced clot formation.

A further object of the invention is to provide an excision catheter which, when used, has a relatively simple regulation of the energy supplied.

Another object of the invention is to provide an excision catheter that is capable of providing the surgeon with information regarding the state of tissue treatment.

The present invention therefore relates to an excision catheter according to claim 1 and an excision apparatus comprising said catheter according to claim 14. Preferred embodiments are defined by the dependent claims.

Aspects, embodiments or examples of the present disclosure that are not within the scope of the appended claims are not part of the invention and are presented for illustrative purposes only.

The idea on which the present disclosure is based is the production of a catheter for the removal of tissues comprising:

- a telescopic tubular body which in turn comprises an outer tubular body and an inner tubular body, concentric with each other, and a rod-type guiding element housed at least partially in the inner tubular body, with at least one free end protruding from the inner tubular body in correspondence with a distal end of the telescopic body;

- a positioning head and an excision head corresponding to the distal end of the telescopic body, the positioning head being located in the vicinity of the free end of the rod-type guide, and the excision head being in the vicinity of the head positioning, in a remote position with respect to the free end;

- a control handpiece at a proximal end of the telescopic body coupled with the guiding element, the removal head, the removal head and the telescopic tubular body;

The removal head comprises at least two removal elements or lobes that can be moved between a resting position in which they are housed in the outer tubular body and an operating position in which they protrude from the outer tubular body as a lobe;

in a characteristic way, each of the removal elements or lobes comprises:

- a continuous removal electrode that extends without interruption along a peripheral peripheral portion of each lobe, substantially along an arc of circumference having a longitudinal axis of the rod-like guiding element in its center

- two lateral portions of the lobe, each being connected to one end of the removal electrode, corresponding to a curved section

the lateral portions and the removal electrode being integral with each other, formed by means of the same folded metal conductor

each individual removal lobe being different from another removal lobe of the removal head, all the removal lobes of the removal head being connected separately to an individual electric power generator to cause radiofrequency removal in an activated state of the electrode of removal.

In this way, the above-mentioned drawbacks are overcome in a brilliant way.

The removal lobes may, in fact, remain in a resting position during insertion and positioning of the catheter, until it has reached the position in which the treatment is to be carried out: in this position, they are contained within an external tubular element of the catheter and have no impediments or protuberances that could complicate the positioning maneuver and the passage through the veins.

Therefore, the small size of the catheter allows the catheter to be easily inserted and positioned.

In this regard, it should be noted that the fact that the lateral portions and the removal electrode are integral with each other, being formed by the same folded metal conductor, allows a considerable reduction in the impediment and, at the same time, an optimal positioning that it allows the reduction of possible clots: the intrinsic elasticity of the cable (or thin sheet) from which it is formed - and all the same for the entire lobe - allows it to be positioned in optimal contact with the tissue that is going to be subjected to a removal treatment, with the result that it is treated uniformly.

The Applicant has discovered that these advantages can be obtained when the lobes are made of Nitinol, produced with a single cable that has a circular section with a diameter D and with the following ratio between diameter D and length L of the active part (the part perimeter of the lobe, that is, the electrode)

The D / L ratio varies between 0.015 and 0.025, preferably equal to about 0.02.

This particular ratio, related to the material with which the lobe is produced (Nitinol), ensures that optimal electrical characteristics are obtained together with an optimal adhesion of the lobe on the surface to be treated, so it is possible to obtain Perfectly straight lesions, without necrotic areas.

With a length L that varies between 10 and 25 mm, the relative optimum diameter preferably varies between 0.20 mm and 0.50 mm, preferably is 0.30 mm.

At the same time, the presence of non-individualized continuous excision electrodes allows the production of excision sections that are much larger than those related to catheters with an excision tip, thereby reducing the duration of treatment time during which the patient must be sedated.

Additionally, with respect to the structures in which the electrode is isolated and applied in a support structure, it can be seen that in this case it is the same structure, the conductor, which acts as an electrode: the latter is therefore evenly distributed ”So that it extends over the entire perimeter portion of the lobe without interruption.

According to a particularly advantageous feature, the removal elements, or at least the relative segments, can be selectively activated, since each is connected to its own specific generator, part of the removal apparatus that also comprises the same catheter: in this way, the surgeon can advantageously choose which and how many of these to activate to repeat the treatment, which therefore can correspond only to the areas that have not been sufficiently treated, avoiding re-treating the areas of the tissue that have already been properly treated or areas that pose a risk to the patient.

In order to allow optimum control of the energy supplied, according to an independent aspect of the invention, additional conductors are contemplated, which are useful for eliminating the parasitic currents that may be generated.

This feature can be advantageously combined with those of the catheter described herein, thus providing an extremely precise removal catheter in the treatment.

In particular, but not exclusively, the removal catheter of the invention is advantageously suitable for the removal of the antrum from the pulmonary veins, to limit or eliminate the phenomenon of atrial fibrillation, thanks to the interruption of the electric currents induced by the veins themselves .

Details on this type of atrial fibrillation treatment, its efficacy and methodology, can be found in the scientific literature, and consequently no further mention of it will be made in the present description.

Other unlimited uses of the catheter of the invention may be, for example, for the removal of renal arteries, as a cure for high blood pressure.

In this case, medical details about the treatment are not provided, since these can be found in the scientific literature.

Other optional advantageous features of the invention are contained in the appended claims, which should be considered as an integral part of the present description.

Brief description of the drawings

The invention is described below with reference to non-limiting examples, provided for illustrative and non-limiting purposes in the accompanying drawings. These drawings illustrate different aspects and embodiments of the present invention and, where appropriate, reference numbers illustrating structures, components, materials and / or similar elements in different figures, are indicated by similar reference numbers.

Figure 1 illustrates a side view of the distal end of the catheter of the invention in a positioning state;

Figure 2 illustrates a side view of the end of the catheter of Figure 1 in an operating state;

Figure 3 illustrates a front view of the catheter of the invention in an insertion state;

Figure 4 illustrates a front view of the catheter of the invention in a positioning state corresponding to that of Figure 1;

Figure 5 illustrates a front view of the catheter of the invention in a state of operation corresponding to that of Figure 2;

Figures 6-10 illustrate side views of variants of a detail of the catheter of the invention;

Figures 11 and 12 illustrate a preferred embodiment of the catheter of the invention, in a side and perspective view;

Figures 13 and 14 illustrate the catheter removal lobes of Figures 11, 12, in a side and perspective view;

Figures 15 and 16 illustrate the positioning head of the catheter of Figures 11, 12, in a side and perspective view;

Figure 17 illustrates a section along the plane AA of Figure 11;

Figures 18 and 19 illustrate sections along planes AA and BB of Figure 13;

Figures 20 and 21 illustrate sections along planes AA, BB and CC of Figure 15.

Detailed description of the invention

Although the invention may undergo various modifications and alternative constructions, some illustrative embodiments are shown in the drawings, and are described in detail below.

However, it should be understood that there is no intention to limit the invention to the specific embodiment illustrated, but rather to the contrary, the invention is intended to cover all modifications, alternative and equivalent constructions that are within the scope of the invention as defined in The claims.

The use of "for example", "etc.", "or" indicates non-exclusive alternatives, without limitation, unless otherwise specified. The use of "understand" means "understand, but is not limited to", unless otherwise specified. With respect to the attached figures, these show an illustrative but not limiting embodiment of the catheter of the invention, indicated as a whole with reference 1.

The catheter 1 comprises a positioning head 2 and an excision head 3, which will be described in more detail below.

The catheter 1 also comprises a handpiece in a proximal position, that is, the control portion that is located outside and that the operator can use to control the action of the catheter itself.

The control handpiece is positioned at a proximal end of the telescopic body 4 and is operatively connected to the guiding element 5, the removal head 3, the positioning head 2, 2 ", 2 '", 2 °, 2 *, 2 ^a and the telescopic tubular body 4; said "operative connection" can be operated in numerous ways, all known to persons skilled in the field, for example, by means of control levers directly or indirectly connected with the above-mentioned parts; consequently, no additional mention will be made in this regard.

The shape of the handpiece has no particular interest for the present invention, since it is produced in a manner analogous to those known in the art; consequently, no additional detail will be provided in this document with respect to the handpiece.

The catheter 1 comprises a telescopic tubular body 4 which in turn comprises: an external tubular body 4a, an internal tubular body 4b, concentric with each other.

A sheath 4c, also eccentric with respect to the tubular bodies 4a, 4b, is also contemplated to cover the outer tubular body.

Tubular bodies 4a and 4b are preferably cylindrical, even if, in general, they can be oval or polygonal (with rounded corners).

The catheter 1 also comprises a rod-type guiding element 5 partially housed in the internal tubular body 4b with a free end 5a protruding from the internal tubular body 4b.

The surgeon uses the rod-type guiding element 5 to guide the movement of catheter 1 when inserted into the patient's veins; this guiding element is, per se, of the known type and no further mention of it will be made.

As can be seen in the figures, the positioning head 2 is located in the vicinity of the free end 5a of the rod-type guide 5, while the removal head 3 is located in the vicinity of the positioning head 2, but in a remote position with respect to the free end 5a; in other words, the removal head 3, when in use, is positioned between the external tubular body 4a and the positioning head 2 (see Figures 2 or 11, 12, for example).

In general, the removal head 3 comprises a plurality of removal elements or lobes 3a.

In the illustrated embodiment there are four removal lobes 3a, but there could also be two, three or more.

A specific feature of the removal elements 3a is that they can be moved, or instead removed, from a resting position in which they are housed in the external tubular body 4a (as in Figures 1, 3 and 4) to a operating position in which they protrude from the external tubular body 4a extending and extending both outward radially and axially towards the positioning head (as in figures 2, 5, 11-14).

The movement between the two positions, the rest and the operation, is carried out thanks to a mechanical control positioned in the handpiece of the device, and which allows the controlled and adjustable extraction of the removal lobes 3a.

In summary, between the internal tubular body 4b and the external tubular body 4a, there is at least one housing chamber 6, in which the lobes 3a are positioned in a resting state, and from which they are extracted to be taken to An operating state.

In some embodiments, a single housing chamber is contemplated for each lobe 3a, while in other embodiments, such as those illustrated, there is only one chamber 6, which in a sectional and front view is substantially in the shape of a crown. circular, since it is formed between the outer tubular bodies 4a and inner 4b.

This allows that when the elements 3a are in a resting state, they are kept removed inside the chamber 6 during the positioning phase of the catheter (see Figures 1, 3 and 4), without creating any obstacle during the passage of the catheter inside the patient's veins, and that they are removed from chamber 6 only when catheter 1 is positioned.

At least one of, preferably all, the removal elements 3a comprise a continuous removal electrode 3b (clearly visible in Figure 5) - or distributed - that extends without interruption over a perimeter portion, preferably peripheral, of each lobe 3a, substantially along an arc of circumference having a longitudinal axis of the rod-like guide element 5, as the center.

In other words, the electrode 3b occupies the entire external body of the lobe 3a, since the folded portions with a greater radius of curvature that connect it with two lateral portions 3c of the lobe 3a, are each connected to one end of the electrode of extirpation (3b).

In a characteristic way, the side portions 3c and the removal electrode 3b are integral with each other, are produced with the same folded metal conductor, to which reference will be made below.

In summary, the lobe is formed by a single folded solid electrical conductor (a cable or a foil), whose perimeter part 3b forms the real electrode and whose lateral parts 3c form the lateral portions of the lobe, which preferably do not contribute to the process of extirpation, even if they are crossed by an electric current. This effect is obtained, for example, by coating the side portions 3c with a layer of an electrical insulating material, preferably a paint (not illustrated in the figures).

Each excision lobe 3a is individual and distinct from another excision lobe of the excision head, and all excision lobes 3a of the head are individually connected to an individual electric power generator to cause radiofrequency excision in an activated state of the electrode of removal 3b. In this way, the amount of energy to be supplied with respect to the desired result can be regulated with extreme precision.

The electrical conductive material that forms the removal lobe 3a is preferably composed of a metal conductor with shape memory, even more preferably a Nitinol cable, a material that is known per se for biomedical use; It should be appreciated that, in general, other metals / metal alloys suitable for this purpose can also be selected.

Since it is essential for the safety and success of the procedure to obtain a continuous and clear removal line without causing superficial necrosis or tissue damage, the ideal conditions to allow this can be obtained when the lobes are Nitinol, each produced with a single cable that has a circular section with a diameter D and with the following ratio between the diameter D and the length L of the active part (the perimeter part of the lobe, or electrode): the D / L ratio varies between 0.015 and 0.025 , preferably equal to about 0.02.

The electrical and mechanical characteristics are therefore optimized with respect to the advantages discussed above.

It should also be mentioned that by joining (ideally) the removal electrodes 3b, they develop substantially along the same circumference, which has the axis of the guiding element 5 as the center; only a few small arcs of this ideal circumference can remain unbound (and therefore inactive in the removal treatment); Thus, during a treatment, an important portion of a blood vessel can be removed leaving only small areas of tissue that do not receive direct treatment.

This can be obtained even more thanks to the fact that, as all lobes 3a are produced with the same conductor and with the same size, the elasticity is such that an optimal adhesion of the lobe to the surface (the lobe, under the action of the force against the tissue, it elastically deforms until it adheres perfectly to the tissue itself, regardless of the rhythmic movements of the same) obtaining optimal results in terms of removal and also in the prevention of clot formation.

In this sense, thanks to the optimum adhesion, a reduced overall amount of energy can be supplied with respect to the cases of the known technique, with a consequent lower heating of the blood that is possibly in contact with the electrode; At the same time, there is also less tissue heating, avoiding the phenomena of necrosis.

These small untreated areas can be subsequently removed by the surgeon, if necessary, for example, by rotating the entire catheter 1 on itself, or more advantageously, only the lobes 3a, keeping the positioning head 2 fixed.

It should be noted that the small angular extension of the arcs in which the removal electrode 3b is not active ensures that the surface treated by each activation of the removal lobes 3a is high, much larger than the known radiofrequency catheters with a tip of removal described above.

This allows a faster treatment of the patient, with the advantages indicated above.

Referring again to the side portions 3c, with reference to Figure 2, it can be seen that, in the preferred embodiment illustrated, they do not develop exactly along an axis perpendicular to that of the guiding element 5 (more specifically, they do not lie in the plane in which the axis of the guiding element 5 is perpendicular): the lateral portions 3c are, in fact, slightly inclined (in a lateral view) towards the free end 5a of the guiding element 5, specifically forming a lobe.

The lateral portions 3c therefore develop preferably, at least partially, along the generatrices of a cone (or of a truncated cone, depending on the cases) whose axis is the longitudinal axis of the guiding element 5.

Thus, also due to the intrinsic elasticity of the elements 3a (whether they are metallic laminates or cables), when the removal segment 3b rests on the tissue to be removed, they are able to cushion, by folding, the Small oscillations or physiological movements (both of the tissue and of the surgeon's hand), always keeping the removal electrode 3b in contact with the tissue itself, guaranteeing reliable contact and consequent effective treatment, with the advantages discussed above.

For each lobe 3a, one of the lateral portions 3c is preferably fixed in the external tubular body, while the other lateral portion extends to (or is connected to) the handpiece, where it is connected to the mechanical activation elements or to the specific generator for this.

Each lobe, in addition to being activated individually, can also be extracted individually from the tubular body 4a in which it is housed in a non-functioning state.

For this purpose, as can be seen in Figures 17, 18, 19, the lateral portion 3c of each lobe is connected both mechanically and electrically with a specific conductor 39.

In the preferred embodiment of Figures 17, 18, the conductor 39 is integral with the lobe 3a, since it is produced with the same Nitinol cable, with the same diameter.

In this preferred embodiment, only one side portion 3c of each lobe extends to the handpiece, the other portion being fixed in correspondence with the terminal end of the body 4a, for example, a terminal bearing; therefore, the preferably sliding bearing 37 houses a side portion of each lobe 3c, while the other terminal portion of the same lobe is fixed to the bearing itself 37.

In the preferred example of Figures 11-21, there are four lobes 3a, therefore, eight side portions 3c, and consequently there will be four conductors 39 extending to the handpiece.

It should be appreciated that, in this preferred embodiment, the conductors 39 of each lobe extend substantially to the handpiece housed inside the body 4a, in the space between it and the body 4b. In this route that passes from the lobes to the handpiece, the conductors 39 are spirally wound in said space between the bodies 4a and 4b.

Each conductor 39 is electrically isolated from the others, so that the activation of one of them does not cause the activation of those nearby.

Again, by making a brief reference to the removal electrodes 3b, in a particularly advantageous embodiment, they can be selectively activated: in summary, each segment 3b and / or each element 3a is connected to a power source individually from the others and can be activated individually; For this purpose, the removal apparatus of the invention comprises several radiofrequency electric power generators equal to that of the lobes, which are connected separately and individually to each generator by means of the conductors 39.

Each electrode 3b and / or each lobe 3a is therefore individually connected to, and can be activated individually by, a source of electrical energy (preferably a radiofrequency generator).

Therefore, the surgeon can choose which electrodes 3b and / or lobes 3a to activate, depending on the treatment conditions, and can also repeat only in correspondence with areas that have not been sufficiently treated and / or prevent the activation of areas that pose a risk to the patient.

In a particularly advanced embodiment, each lobe 3a can be advantageously moved individually (with respect to the others) between the resting state and the operating state, extracted.

This allows the surgeon to remove only the removal lobes 3a that are necessary, for example, when the size / shape of the tissue to be removed has physiological characteristics that make it advisable.

The removal lobes 3a are optionally rotatably associated with the telescopic body 4, so that they can be rotated without also causing the rotation of the body 4 and / or the positioning head 2; this is obtained, for example, in the case of the embodiment of figures 11-21, causing the terminal bearing 37 (provided with seats in which the conductors 39 pass axially before being connected to the portions 3c) rotate freely with respect to the body 4a.

The lobes 3a are preferably controlled by the handpiece of the device, by means of a mechanical, or electrical or pneumatic control.

This allows to obtain a great flexibility of use together with considerable precision: when the surgeon has positioned the catheter 1 in an operating position, it keeps it in the correct position thanks to the positioning head 2 (to which an additional reference will be made below ), and can proceed with the treatment of the various parts of the tissue, extracting, rotating and activating only the 3a lobes, without having to repeat the positioning phase each time.

This contributes, among others, to make the treatment even faster, with the advantages indicated above.

According to an optional and advantageous feature, also independently of the other features of the invention, at least one - preferably a plurality - of the additional conductors 38, partially housed in the telescopic tubular body 4, shown in the preferred embodiment of the figures, is contemplated. 11-21. The additional conductors 38 are also housed in the body 4a, in the space between it and the body 4b, adjacent to the conductors 39, in particular spirally arranged and interspersed with the latter.

Said additional conductors 38 are not in electrical contact with the lobes 3a and serve to reduce the parasitic currents and allow a better control of the energy supplied to each lobe during the operation phase of the catheter.

These advantages are most strongly perceived when the removal lobes are used, such as those described, which are independently connected to the generators; in this way, parasitic currents can be avoided, which could make the treatment less accurate.

This advantage is offered when the removal apparatus comprises individualized electrodes and also when the electrodes are contiguous, as in the catheter described above.

In the electrodes, parasitic currents are generated that are not fed due to those that are being fed at the same time by the respective generator, and also cause the activation of the electrodes that, on the other hand, should not be powered.

The additional conductors 39 are preferably completely contained in the telescopic tubular body 4 and leave it only on the side of the handpiece.

Each additional conductor is preferably folded in a "U" shape inside the body, with the two free ends leaving the proximal side and the folded part extending in the tubular body to its end; alternatively and preferably, all or only part of the additional conductors may be electrically connected to each other.

Additional conductors 39 are preferably copper wires.

When the electrode supply conductors are spirally wound in the body 4, the additional conductors 38 are interposed between them, so that each supply conductor 39 of a lobe is adjacent, on the two opposite sides, to the two branches of the same - or of different - additional conductors 38. This arrangement, shown in detail in Figures 17, 18, 19, makes it possible to completely or almost completely eliminate the phenomenon of the parasitic currents described above, so that the removal treatment can Be controlled with extreme accuracy.

Finally, according to another optional and advantageous feature, the removal head 3 comprises at least one contact sensor, capable of measuring contact with the surface to be treated, carrying out the treatment with greater precision.

In particular, in one embodiment, said contact sensor is a capacitive sensor, which indirectly measures the percentage of electrode 3b that is in contact with the tissue.

If the removal is obtained by means of radiofrequency (RF), for example, the same electrode 3b acts as the electrode of the capacitive sensor: by passing a control current, it is in fact possible to reveal whether or not it is in contact with the tissue.

Now, with respect to the positioning head 2, it comprises a plurality of removable positioning arms 2a.

Said arms 2a pass from a rest position, in which they are housed in the internal tubular body 4b, to an extracted operative position, in which they project radially from it.

Also in this case, analogously to the removal head 3, the removable positioning arms 2a remain removed during the insertion phase of the catheter into the vein, until it has reached the area to be treated, so that they represent an obstacle during this phase, and are extracted to maintain the position reached, plugged against the walls of the vein / artery to be treated.

In particular, the removable arms 2a are preferably housed between the internal tubular body 4b and the rod-like guide element 5.

The removable arms 2a form a kind of positioning cage, intended for the support inside the vein, so that the removal head is properly maintained in position in correspondence with the vein opening itself.

In the illustrated embodiment, there are advantageously eight removable positioning arms 2a, but, more generically, there could be two, three, four or more.

Also in this case, the removable positioning arms 2a are controlled, in the extraction / reinsertion movement (from the rest position to the operating position and vice versa) by means of a mechanical system located in the handpiece of the device, and that allows the controlled and adjustable output of the removable elements 2a.

In other embodiments, the positioning head is an inflatable body (not shown) that is expanded from the resting position to the operating position, like a balloon.

Also in this case, the inflatable body is preferably housed, in the resting state, inside the tubular body 4.

The advantages of using a positioning head 2 provided with arms 2a, with respect to the inflatable body, are, in the first place, related to the fact that the first solution does not block the passage of blood in the vein, as it would be the case, on the contrary, with an internally inflated balloon (possibly causing clots or a phenomenon of pulmonary hypertension).

In addition, the inflatable body has the advantage of being capable of being filled with a radiopaque fluid for a better and more accurate visualization.

According to a particularly advantageous characteristic, regardless of its practical embodiment, the positioning head 2 comprises at least one sensor capable of revealing the electrical potentials of the tissue, consequently allowing the totality of the excision performed to be revealed.

This sensor can be produced in various ways, depending on the case.

For example, it can be an electrode applied to the arms 2a or to the inflatable body.

Alternatively, when the positioning head 2 comprises metal arms 2a, these, in practice, form the electrode for detection, whereby the electrical potentials of the vein are revealed and the isolation of the vein is verified during and at end of treatment

With regard to the positioning head 2 described above, it is interesting to appreciate how it comprises, both in the embodiment described above and in its variants 2 ", 2"', 2 °, 2 *, 2A, which will be briefly described then at least one removable positioning arm 2a (and 2a ", 2a"', 2nd, 2a *, 2aA in the variants described below) that can be moved between a resting position, in which it adheres to the guide element of rod type 5 and is housed in the body 4 of the catheter, and an enlarged operating position, in which it protrudes from the guide element of rod type 5, expanding in a radial direction.

The rod-type guiding element 5 slides in the internal tubular body 4b; The positioning head 2, 2 ”, 2” ', 2 °, 2 *, 2a, in the resting state, has a size such that it can be inserted into the internal tubular body 4b.

The catheter 1 can then be inserted into the vein so that it occupies a minimum space and does not have bumps that could obstruct its passage in the patient's body, subsequently, when the catheter 1 is in the area to be treated, the element Rod type 5 is removed from the internal tubular body 4b and, when the catheter has reached a correct position, in which it must be fixed, the positioning head 2, 2 ”, 2” ', 2nd, 2 *, 2nd, it is expanded, or rather, its arms 2nd, 2nd, 2nd, 2nd, 2nd *, 2nd are expanded, moving from a resting position to an expanded position, and can be supported against surrounding tissues, so that catheter 1 be held in position.

The synergy of the advantages derived from the combined use of an excision head 3 and a positioning head 2, according to the invention, are therefore evident.

With regard to the description of the alternative forms of the positioning head, reference should be made to Figures 6 through 10.

In the figures, catheter 1 is shown with the removal head in a resting state and, for reasons of clarity, only the positioning head is illustrated.

In this regard, it should be appreciated that, in order to avoid impediments in the present description, no further mention is made below of the elements and features in common with head 2 and arms 2a, already presented above; It should also be mentioned that the same parts illustrated in the previous figures are indicated with the same reference numbers.

Fig. 6 shows a positioning head 2 "in an expanded state, comprising only one arm 2a", in the form of a spiral that develops around the rod-like element 5.

When in an extracted state, arm 2a ”rests with its loop on the tissue, helping to keep catheter 1 in position.

Figures 7, 8, 9 and 10 show, in an expanded state, the positioning heads 2 "', 2 °, 2 * and 2A, each of which comprises arms 2a"', 2nd, 2nd * and 2aA that extend according to different geometries around the rod type element 5:

the arms 2a "', in an extended state, each form a kind of rectangle (in a side view) with the rounded edges, the arms 2nd, in an extended state, each form a kind of semicircle (in a side view),

arms 2a *, in an extended state, each form a kind of isosceles triangle (in a side view),

the arms 2aA, in an extended state, each form a kind of half-arm (in a side view) with rounded edges.

In addition, it should be noted that each removable arm 2a, 2a ", 2a" ', 2nd, 2nd * and 2aA is arched (even if it does not develop according to a real circumference arc, except for the 2nd arms) and extends substantially between said internal tubular body (4b) and said free end (5a) of said rod type element (5).

Even if two arms are shown in the examples of these variants, three, four or more arms can be contemplated, similar to the arms 2a described above.

With reference to FIGS. 11-21, which show a preferred embodiment, it should be appreciated that, in a similar manner, the conductors 39 of the lobes, each arm 2a of the head 2 also extends in the body 4b to the handpiece by means of elongated spiral-shaped portions 29.

Each elongated portion is preferably integral with the respective arm 2a and is produced with the same material, preferably a conductor such as Nitinol or the like.

Inside the body 4b, more specifically in the space between it and the guide wire 5, each elongated portion 29 is electrically isolated from the others, so that the arms 2a can reveal (or transmit) possible electrical signals independently of each other. .

Furthermore, in the attached preferred embodiment, additional second conductors 28 are contemplated for positioning head 2, with advantages similar to those described above for the first additional conductors 38 (with respect to parasitic currents).

These additional conductors 28 are developed on a propeller having the same helical pitch and the same diameter with respect to the elongated portions 29, and are interspersed with the latter, so that each elongated portion 29 of an arm 2a is adjacent, in the two opposite sides, two branches of the same additional driver (s) 28 - or of a different one -.

In summary, the aspects related to the reduction of the phenomena of the parasitic currents are therefore reduced or even canceled.

The additional conductors 28 are preferably made of copper, preferably in the form of U-folded cables inside the body 4b (or, alternatively, preferably all or part of them are electrically connected to each other), between it and the cable guided, in a manner analogous to the additional conductors 38 described above.

In the excision apparatus, the additional dissipating conductors 28, 38 mentioned above are preferably electrically grounded.

Therefore, the objectives indicated above have been achieved.

Claims (14)

1. A catheter (1) for tissue removal comprising: - a telescopic tubular body (4) which in turn comprises an outer tubular body (4a) and an inner tubular body (4b) concentric with each other, and a rod-type guiding element (5) housed at least partially in the body inner tubular (4b) with at least one free end (5a) protruding from the inner tubular body (4b) in correspondence with a distal end of the telescopic body (4); - a positioning head (2, 2 ”, 2” ', 2 °, 2 *, 2A) and an excision head (3) in correspondence with the distal end of the telescopic body (4), the positioning head ( 2, 2 ”, 2 '”, 2 °, 2 *, 2A) located in the vicinity of the free end (5a) of the rod-type guide, and the removal head (3) being in the vicinity of the positioning head (2, 2 ”, 2” ', 2 °, 2 *, 2A), in a remote position with respect to the free end (5a); - a control handpiece at a proximal end of the telescopic body (4) coupled with the guiding element (5), the removal head (3), the positioning head (2, 2 ", 2" ', 2 °, 2 *, 2A) and the telescopic tubular body (4); wherein the removal head (3) comprises at least two removal elements or lobes (3a) that can be moved between a resting position in which they are housed in the outer tubular body (4a) and an operating position in the one that protrude from the outer tubular body (4a) as a lobe; each of the removal elements or lobes (3a) comprising: - a continuous removal electrode (3b) that extends without interruption over a peripheral peripheral portion of each lobe (3a), substantially along an arc of circumference having a longitudinal axis of the rod-type guiding element (5) as its center; - two lateral portions (3c) of the lobe (3a) connected, each, with one end of the removal electrode (3b), corresponding to a curved section, each excision lobe (3a) being individual and distinct from another excision lobe (3a) of the excision head, all excision lobes (3a) of the excision head being connected separately to an individual electric power generator to cause an individual radiofrequency excision on an excision electrode in the activated state (3b), characterized by that the lateral portions (3c) and the removal electrode (3b) are integral with each other, formed by means of the same folded metal conductor, and in which Each removal lobe (3a) is produced with a single Nitinol cable that has a circular section with a diameter D, and, since L is the linear length of the removal electrode, there is the following D / L ratio, which varies between 0.015 and 0.025. 2. The catheter (1) according to the preceding claim, wherein said D / L ratio is equal to about 0.02. 3. The catheter (1) according to one or more of the preceding claims, wherein the two lateral portions (3c) of each lobe (3a) are coated with an electrical insulating material, preferably an insulating paint. 4. The catheter (1) according to one or more of the preceding claims comprising, for each lobe, at least one conductor (39) extending to the handpiece to individually activate each lobe, wherein said conductor (39 ) extends inside the outer body (4a), in the space between it and the inner body (4b), preferably arranged in a spiral. 5. The catheter (1) according to one or more of the preceding claims comprising, for each lobe, at least one additional first conductor (38) housed at least partially in the telescopic tubular body (4), and intended to extend preferably from the handpiece to the end of the external body (4b). 6. The catheter (1) according to the preceding claim, wherein each first additional conductor (38) is spirally developed inside the external body (4a), and wherein said conductors (39) alternate with at least an additional conductor (38), inside said external body (4a). 7. The catheter (1) according to one or more of the preceding claims, wherein each lobe (3a) can be moved individually with respect to the others between the resting state and the operating state (removed). 8 . The catheter (1) according to one or more of the preceding claims, wherein the removal lobes (3a) are rotatably associated with the telescopic body (4) so that they can be rotated without causing the body (4) and / or the positioning head (2, 2 ", 2"', 2 °, 2 *, 2A) rotate as well. 9. The catheter (1) according to one or more of the preceding claims, wherein the positioning head (2, 2 ", 2"', 2 °, 2 *, 2A) comprises at least one removable positioning arm ( 2nd, 2nd ”, 2nd”, 2nd, 2nd *, 2nd), being said removable positioning arm (2nd, 2nd ", 2nd", 2nd, 2nd *, 2nd) movable between a resting position, in which it is housed in the inner tubular body (4b), and an extracted operating position , in which it protrudes radially from the inner tubular body (4b). 10. The catheter (1) according to one or more of the preceding claims, wherein the positioning head (2, 2 ", 2" ', 2 °, 2 *, 2A) comprises at least one sensor capable of revealing the electrical potentials of the tissue and allow the entire removal to be revealed. 11. The catheter (1) according to the preceding claim, wherein said arms (2nd, 2nd, 2nd, 2nd, 2nd *, 2nd) are metallic and form the sensing electrode. 12. The catheter (1) according to the preceding claim, wherein each arm is connected with at least one elongated portion (29) extending to the handpiece, is housed in the inner body (4b) and preferably has a shape of spiral 13. The catheter (1) according to claim 12, wherein additional second conductors (28) are contemplated for the positioning head (2), which are preferably spirally developed and interspersed with said elongated portions (29). 14. An apparatus for tissue removal comprising a catheter according to one or more of claims 1 to 13 and at least one electric power generator for each lobe of said catheter, electrically connected to said lobe.